People

Dylan GaetaGraduate Student

Biography

I graduated from the University of Rochester in 2016 with bachelor's degrees in Chemistry and Applied Mathematics, and then came to the University of Chicago later that year to start my Ph.D. work with Prof. Liz Moyer. I'm interested in topics relating to climate change that span from understanding Earth's behavior as a physical system to discerning the humanitarian implications of it.

Research Interests

I'm broadly interested in the various forcings and feedbacks that govern the climate system, though my work focuses on the role of clouds and atmospheric water vapor in particular. If we are to gain a better understanding of how the climate system will respond to a greenhouse gas-induced radiative forcing, we need to develop 1) a better understanding of the chemical and physical processes that govern cloud behavior, and 2) more sophisticated methods for representing that behavior in climate models.

Clouds are an inherently difficult body to model; their important characteristic properties span from sub-micron scale to kilometer scale – spatial scales that differ by up to twelve orders of magnitude. Their behavior is heavily parameterized in climate models, which leads to varying estimates of the cloud feedback parameter, and thus large uncertainty in the climate sensitivity - a metric we traditionally define as the equilibrium globally averaged surface temperature change resulting from a doubling of the atmospheric CO2 concentration.

Clouds are, in fact, the largest source of uncertainty in our attempts to quantify Earth’s climate sensitivity. They possess a unique quality in that they can either warm or cool Earth’s surface, depending on their composition and spatial location in the atmosphere (particularly in the vertical dimension). High altitude cirrus clouds tend to warm the surface by absorbing outgoing infrared radiation propagating from below, while low-level stratus and cumulus clouds tend to cool the surface by reflecting incoming solar radiation back to space. Quantifying the net impact that the competing warming and cooling mechanisms have on Earth’s radiation budget (both globally and regionally) is a crucial task if we are to better understand past and future climatic changes.

My current research focuses on the convective processes that control the distribution of water vapor in the atmosphere and on the mechanisms of high altitude cirrus cloud formation (particularly near the tropical tropopause). The isotopic composition of water vapor is an extremely useful tracer of both these processes, and so my work involves the development and utilization of a novel spectroscopic instrument for taking rapid in-situ measurements of water vapor isotopologues (HDO and H218O) in the tropical upper troposphere/lower stratosphere. This instrument will participate in the summer 2017 StratoClim field campaign, with the goal of acquiring in-situ measurements via aircraft of the water vapor isotopic abundance in the upper troposphere-lower stratosphere region where the Asian summer monsoon is active.